Ketel Uap Pendahuluan

Sebagai salah satu peralatan transportasi kapal membutuhkan penggerak. Penggerak kapal modern dikenal

dengan motor penggerak utama atau motor induk atau main engine. Motor penggerak utama, membutuhkan

peralatan peralatan pendukung untuk mampu bekerja dengan baik. Kebutuhan bahan bakar misalnya, untuk

memindahkan bahan bakar dari tanki bahan bakar menuju ke mesin penggerak utama membutuhkan beberapa

peralatan, misalnya saja pompa. Tanpa adanya peralatan bantu tentu motor induk tidak akan bisa bekerja dengan

baik.

Jika pompa digunakan untuk memindahkan bahan bakar dari tanki bahan bakar menuju mesin penggerak utama,

bagaimana dengan ketel uap? Ketel uap memiliki peran yang penting juga dalam operasional mesin penggerak

utama. Bahan bakar yang dipindahkan oleh pompa pada umumnya adalah bahan bakar yang memiliki viskositas

yang tinggi, viskositas ini mempengaruhi kekentalan bahan bakar. sehingga jika nilai viskositas tidak diturunkan

maka bahan bakar akan mengental dan sulit untuk dipompa dan sulit untuk masuk menuju nozzle bahan bakar mesin

penggerak utama. Untuk menurunkan kekentalan ini maka bahan bakar harus dipanaskan terlebih dahulu. Proses

pemanasan bahan bakar tidak boleh menggunakan api, karena bahan bakar akan dengan mudah terbakar. Proses

pemanasan bahan bakar tersebut menggunakan aliran uap panas yang dialirkan melalui pipa –pipa yang dipasang

dalam tangki bahan bakar atau pada jalur aliran bahan bakar menuju mesin penggerak utama. Uap panas yang

dialirkan tersebut diperoleh dari boiler atau ketel uap.

Definisi

Ketel Uap (bahasa Inggris:boiler) adalah alat untuk menghasilkan uap air, yang akan digunakan untuk pemanasan

atau tenaga gerak. Bahan bakar pendidih bermacam-macam dari yang populer batubara dan minyak bakar, sampai

listrik, gas, biomasa, nuklir dan lain-lain.

Aplikasi Ketel Uap di Kapal:

Fungsi utama ketel uap di kapal adalah untuk menghasilkan uap. Uap yang dihasilkan oleh boiler selain sebagai

pemanas bahan bakar seperti yang telah disebutkan, juga bisa digunakan untuk menggerakkan turbin uap yang juga

digunakan sebagai motor penggerak utama kapal.

Ketel uap memanaskan cairan yang ada di dalamnya dan mengubah cairan tersebut menjadi uap. Uap yang telah

terbentuk kemudian dialirkan ke bagian bagian yang membutuhkan, bisa untuk menggerakkan turbin uap atau

digunakan sebagai sumber panas.

Dikapal pemakaian uap dapat untuk berbagai tujuan :

1. Menghasilkan daya untuk penggerak utama dan penggerak bantu

2. Untuk peralatan pemanas ( pemanas ruangan, bahan bakar, muatan minyak dln )

3. Pada kapal tanker digunakan sebagai pembersih tangki minyak ( Tank Cleaning )

Keterangan Gambar: •

Superheater: Pemanas lanjut •

Economizer: aliran gas panas dari gas buang mesin penggerak utama. •

Feedwater: cairan yang akan dipanaskan dalam boiler •

Condenser: alat untuk mengubah uap menjadi cairan •

Heater: pemanas Proses dalam sebuah ketel uap:

Salah satu ukuran boiler: DATA SHEET series© Aalborg Industries 1998, rev.: 3.0, January 2006

Steam boilerPreliminaryAs one boat transportation equipment requires driving. Known activator of modern ships with main engine or main engine or main engine. The main motor, requires equipment capable of supporting equipment to work properly. Needs fuel for example, to move the fuel from the fuel tank to the main engine require some equipment, such as pumps. Without the main engine auxiliary equipment would not be able to work well.If the pump used to transfer fuel from the fuel tank to the engine prime mover, how to steam boiler? Boiler has an important role also in the main engine operations. Fuel is transferred by the pump in general is the fuel that has a high viscosity, viscosity affects the viscosity of fuel. so if the value of viscosity is not lowered then the fuel will be thickened and difficult to pump and difficult to enter into the fuel nozzle engine prime mover. To reduce this viscosity, the fuel must be heated first. The process of heating fuel may not use fire, because fuel will easily burn. The process of heating fuel using hot steam flow that is channeled through pipes installed in the fuel tank or the fuel flow path toward the main engine. Steam heat flow is derived from the boiler or steam boiler.DefinitionBoiler (English: boiler) is a tool to generate steam, which will be used for heating or power of motion. Fuel pendidih variety of popular coal and fuel oil, to electricity, gas, biomass, nuclear and others.Boiler Applications in Ships:The main function of the boiler on the ship is to generate steam. Steam produced by boiler other than as a heating fuel as already mentioned, can also be used to drive steam turbines are also used as the main driver of the boat.Boiler heating fluid in it and turn the liquid into vapor. Steam that has been formed then poured into the parts that need, able to drive a steam turbine or used as a heat source.Ship to use steam for various purposes:1. Generate power for driving the main and auxiliary drive2. For heating equipment (heating, fuel, oil cargo DLN)3. In the tanker is used as a cleaning oil tanks (Tank Cleaning)

Image Description:•Superheater: Heating up•Economizer: hot gas flow from the main engine exhaust gas.•Feedwater: the liquid to be heated in a boiler•Condenser: a tool to change the vapor into liquid•

Heater: heaterProcess in a steam boiler:

boiler adalah wadah tertutup di mana air atau cairan lainnya dipanaskan setelah menjadi sasaran tekanan. Uap atau cairan panas ini kemudian disebarkan keluar dari boiler untuk pemanfaatannya dalam pemanas. Bola keamanan merupakan bagian integral dari boiler dan sangat penting untuk mencegah overheating dan kerusakan yang terjadi setelah boiler yang dapat disebabkan oleh kemungkinan ledakan.

Dalam sistem boiler listrik pipa atau tubing koneksi yang diperlukan untuk mengedarkan cairan yang membawa panas. boiler listrik yang dibangun sedemikian rupa sehingga mereka cocok untuk sistem dual-fluida. boiler seperti ini biasanya dapat diinstal dengan segala macam di lantai hydronic sistem pemanas.

Listrik boiler konvensional dapat diinstal dengan pinggir dan radiator. Karena ukuran kompak boiler listrik dapat digunakan untuk renovasi atau proyek-proyek konstruksi baru. Orang yang menggunakan boiler listrik memiliki keuntungan tambahan dalam hal menjadi terjamin lingkungan yang bersih.

Listrik boiler tidak memancarkan apapun asap beracun. Eco-keramahan boiler listrik telah membuat mereka sangat populer di kalangan pengguna mereka. Orang yang menggunakan boiler listrik tidak perlu menghadapi pengalaman yang tidak menyenangkan menjadi sasaran karbon monoksida yang merupakan gas sangat beracun.

Karbon monoksida adalah dipancarkan dari hampir segala macam peralatan pembakaran tetapi tidak listrik boiler. boiler pengguna Listrik tidak perlu khawatir tentang penyusunan kembali lampu pilot perpipaan gas atau ventilasi yang merupakan masalah umum dalam peralatan pembakaran.

boiler is a closed container in which water or other liquid is heated after a target pressure. Steam or hot fluid is then distributed out of the boiler for its utilization in a heater. Ball security is an integral part of the boiler and is very important to prevent overheating and damage that occurs after a boiler that can be caused by the possibility of explosion.

In a system of electric boiler pipe or tubing connections needed to circulate the fluid that carries heat. electric boilers are constructed in such a way that they are suitable for dual-fluid system. Such boilers can usually be installed with all kinds of hydronic floor heating system.

Conventional electric boilers can be installed with edge and radiator. Because of the size of compact electric boilers can be used for renovation or new construction projects. People using electric boilers have an additional advantage in terms of a guaranteed clean environment.

Electric boiler does not emit any toxic fumes. Eco-friendliness of electric boilers have made them very popular among their users. People using electric boilers do not have to face the unpleasant experience

to be targets of carbon monoxide which is a highly toxic gas.

Carbon monoxide is emitted from almost all kinds of electrical equipment but not burning boilers. Electric boiler users do not have to worry about reconfiguring pilot light gas piping or ventilation is a common problem in combustion equipment.

Definition: Boiler

Boiler \Boil"er\, n.A sunken reef; esp., a coral reef on which the sea breaksheavily.[Webster 1913 Suppl.]

Boiler \Boil"er\, n.1. One who boils.[1913 Webster]

2. A vessel in which any thing is boiled.[1913 Webster]

Note: The word boiler is a generic term covering a greatvariety of kettles, saucepans, clothes boilers,evaporators, coppers, retorts, etc.[1913 Webster]

3. (Mech.) A strong metallic vessel, usually of wrought ironplates riveted together, or a composite structurevariously formed, in which steam is generated for drivingengines, or for heating, cooking, or other purposes.[1913 Webster]

Note: The earliest steam boilers were usually spheres orsections of spheres, heated wholly from the outside.Watt used the wagon boiler (shaped like the top of acovered wagon) which is still used with low pressures.Most of the boilers in present use may be classified asplain cylinder boilers, flue boilers, sectional andtubular boilers.[1913 Webster]

Barrel of a boiler, the cylindrical part containing the

flues.

Boiler plate, Boiler iron, plate or rolled iron of abouta quarter to a half inch in thickness, used for makingboilers and tanks, for covering ships, etc.

Cylinder boiler, one which consists of a single ironcylinder.

Flue boilers are usually single shells containing a smallnumber of large flues, through which the heat eitherpasses from the fire or returns to the chimney, andsometimes containing a fire box inclosed by water.

Locomotive boiler, a boiler which contains an inclosed firebox and a large number of small flues leading to thechimney.

Multiflue boiler. Same as Tubular boiler, below.

Sectional boiler, a boiler composed of a number ofsections, which are usually of small capacity and similarto, and connected with, each other. By multiplication ofthe sections a boiler of any desired capacity can be builtup.

Tubular boiler, a boiler containing tubes which form flues,and are surrounded by the water contained in the boiler.See Illust. of Steam boiler, under Steam.

Tubulous boiler. See under Tubulous. See Tube, n., 6,and 1st Flue.[1913 Webster]

Dictionary: quick_english-indonesianDefinition: boiler

ketel uap

Dictionary: WordNetDefinition: boiler

boilern 1: sealed vessel where water is converted to steam [syn: {steamboiler}]2: a metal pot for stewing or boiling; usually has a lid [syn:kettle]

Definisi: Boiler

Boiler \ Rebus "er \, n.Sebuah terumbu cekung;. Esp, terumbu karang yang laut istirahatberat.[Webster 1913 Suppl.]

Boiler \ Rebus "er \, n.1. Satu yang bisul.[1913 Webster]

2. Sebuah kapal di mana setiap hal direbus.[1913 Webster]

Catatan: Kata boiler adalah istilah generik yang mencakup besarberbagai ceret, panci, boiler pakaian,evaporator, tembaga, retor, dll[1913 Webster]

3. (Mech.) Sebuah kapal logam yang kuat, biasanya besi tempapiring terpaku bersama, atau struktur kompositberbagai terbentuk, di mana uap dihasilkan untuk mengemudimesin, atau untuk pemanasan, memasak, atau tujuan lainnya.[1913 Webster]

Catatan: ketel uap awal biasanya lingkungan ataubagian dari bola, dipanaskan sepenuhnya dari luar.Watt menggunakan boiler gerobak (berbentuk seperti puncakgerobak tertutup) yang masih digunakan dengan tekanan rendah.Sebagian besar boiler yang digunakan ini dapat diklasifikasikan sebagaipolos silinder boiler, boiler buang, sectional dantubular boiler.

[1913 Webster]

Barel boiler, bagian silinder berisiflues.

Boiler plat, besi Boiler, plat atau besi digulung sekitarseperempat setengah inci di ketebalan, digunakan untuk membuatboiler dan tangki, untuk kapal meliputi, dll

Cylinder boiler, salah satu yang terdiri dari besi tunggalsilinder.

boiler asap biasanya kerang tunggal berisi kecilflues jumlah besar, di mana panas baiklolos dari api atau kembali ke cerobong asap, dankadang-kadang berisi kotak api tertutup oleh air.

Boiler lokomotif, boiler yang mengandung api tertutupkotak dan sejumlah besar flues kecil yang mengarah kecerobong.

Multiflue boiler. Sama seperti boiler berbentuk tabung, di bawah ini.

Sectional boiler, boiler terdiri dari sejumlahbagian, yang biasanya kapasitas kecil dan sejenisnyauntuk, dan terhubung dengan, satu sama lain. Dengan perkalianbagian boiler dari setiap kapasitas yang diinginkan dapat dibangunup.

Tubular boiler, boiler mengandung tabung yang membentuk flues,dan dikelilingi oleh air dalam boiler.Lihat Illust. boiler Uap, di bawah Uap.

Tubulous boiler. Lihat di bawah Tubulous. Lihat Tube, n., 6,dan 1 asap.[1913 Webster]

Dictionary: quick_english-indonesianDefinisi: boiler

ketel UAP

Dictionary: WordNetDefinisi: boiler

keteln 1: kapal disegel dimana air diubah menjadi uap syn [: {uapboiler}]2: panci logam untuk kesal atau direbus, biasanya memiliki [syn tutup:ketel]

noun

1. sealed vessel where water is converted to steam Terjemahkan

source: wordnet30

2. a metal pot for stewing or boiling; usually has a lid Terjemahkan

source: wordnet30

3. One who boils. Terjemahkan

source: webster1913

4. A sunken reef; esp., a coral reef on which the sea breaks heavily

kata benda1. kapal disegel dimana air diubah menjadi uap Terjemahkansumber: wordnet30

2. panci logam untuk kesal atau direbus, biasanya memiliki tutup Terjemahkansumber: wordnet30

3. Satu yang bisul. Terjemahkansumber: webster1913

4. Sebuah terumbu cekung;. Esp, terumbu karang yang rusak berat laut

Steam boiler adalah sebagai alat unuk mentransfer panas pembakaran bahan bakar

ke air ketel untuk mendapatkan uap.

Klasifikasinya :

A. 1. Fire tube Boiler

2. Water tube Boiler

B.

1. External fired Boiler, Perapian diluar

2. Internal fired Boiler, Perapian didalam

C. 1. Vertical type (Tipe Vertikal)

2. Horizontal type ( Tipe Horizontal)

D. 1. Single tube (1 fire tube/ water tube)

2. Multi tube (banyak fire tube/ water tube)

E. 1. Natural circulation (Sirkulasi alami)

2. Forced circulation (Sirkulasi Paksa)

F. 1. Stationary Boiler

2. Mobile type Boiler

G. Menurut sumber panas pembakaran

1.Coal (Batubara)

2. Oil (Minyak) & gas

3. Nuclear (Nuklir)

4. Dll

Steam boilers are as under on heat transfer equipment burning fuelto the boiler water to get steam.Classification:A. 1. Fire tube Boilers2. Water Tube Boilers

B.1. External fired boilers, fireplace outside2. Internal fired boilers, fireplace inC. 1. Vertical type (Vertical Type)2. Horizontal type (Horizontal Type)D. 1. Single tube (1 fire tube / water tube)2. Multi tube (a lot of fire tube / water tube)E. 1. Natural circulation (natural circulation)2. Forced circulation (Forced Circulation)F. 1. Stationary Boiler2. Mobile Type Boilers

G. According to the source of combustion heat1.Coal (Coal)2. Oil (Petroleum) & gas3. Nuclear (Nuclear)4. Etc.

boiler Lancashire

Boiler ini adalah type tidak dapat bergerak (tsationary), model fire tube, pembakaran dalam, mendatar dan menggunakan sirkulasi alami. Boiler ini dipakai dimana tekanan kerja dan power/ tenaga yang dibutuhkan sedang. Boiler ini memiliki shell/ selongsong silindris dengan dimeter 1.75 – 2.75 meter. Panjangnya bervariasi dari 7.25 – 9 meter. Boiler ini memiliki 2 cerobong dalam dengan diameter sekitar 0.4 kali diameter selongsong. Boiler tipe ini disusun dengan batu tahan api yang membentuk cerobong luar, maka bagian dari permukaan pemanasan berada di luar selongsong.

This is the type of boiler can not move (tsationary), model fire tube, combustion, landscape and use natural circulation. These boilers are used where the pressures of work and power / energy required being. This boiler has a shell / shell cylindrical with dimeter 1.75 - 2.75 meters. Its length varies from 7:25 - 9 meters. This boiler has 2 chimney inside with a diameter of about 0.4 times the diameter of the sheath. Boilers of this type have been prepared with refractory stones that form the outer chimney, then part of the heating surface is outside the shell.

Boiler Cornisha.Boiler Cornish memiliki 1 cerobongb.Diameter cerobong Boiler Cornish sekitar 0.6 x dimeter selongsongc.Boiler cornish umumnya antara 1 – 2 meter dan panjangnya bervariasi antara 5 –7.5meter.d.Kapasitas dan tekanan kerja lebih rendah.Boiler Lancashirea.Boiler Cornish memiliki 2 cerobong.b.Diameter cerobong Boiler Lancashire sekitar 0.4 x dimeter selongsong.c.Boiler Lanchasire panjangnya antara 1.75 – 2.75 meter dan panjangnya bervariasidari7.25 – 9 meter.d.Tenaga kerja dan power/ tenaga yang dibutuhkan sedangCornish Boilera.Cornish boiler has a flueb.Cornish Boiler chimney diameter of about 0.6 x dimeter sleevesc.Cornish boilers are generally between 1-2 meters and the length varies between 5 -7.5meters.d.Kapasitas and lower working pressure.Lancashire Boilera.

Cornish boiler has 2 chimney.b.Lancashire boiler flue diameter of about 0.4 x dimeter sleeves.c.Boiler Lanchasire length between 1.75 - 2.75 meters and the length variesof7:25 - 9 meters.d.Labor and power / energy required is

Boiler lokomotif Locomotive boilerBoiler ini terdiri dari sebuah selongsong atau tong dengan diameter 1.5 meter dan panjang 4 meter. Batu bara diumpankan ke kotak api melalui pintu api dan dibakar pada kisi – kisi. Cerobong gas dari kisi-kisi dibelokkan oleh lengkungan batu, sehingga semua bagian kotak api terpanaskan dengan baik. Ada sekitar 157 tube tipis atau tube F (diameter 47.5 mm) dan 24 tube tebal atau tube panas lanjut G (diameter 130 mm). Setelah melalui tube ini gas memasuki kotak asap (smoke box). Gas kemudian menuju atmosfer melalui cerobong asap. Tong (barrel) berisi air di sekitar tube, dipanaskan oleh gas asap dan diubah menjadi uap. This boiler consists of a sleeve or barrel with a diameter of 1.5 meters and 4 meters long. Coal is fed into the fire box through the door of the fire and burned on the lattice - lattice. Stack gas from the lattice deflected by a stone arch, so that all parts of the fire box with a well heated. There are about 157 thin tube or tube F (diameter 47.5 mm) thick and 24 tube or tube of heat-up G (diameter 130 mm). After going through this tube the gas entering the smoke box (smoke box). Gas then to the atmosphere through the chimney. Tong (barrels) of water around the tube, heated by gas fumes and is converted into steam.

Boiler Babcock dan Wilcock tube airBoiler ini terdiri dari drum uap dan drum air (1). Drum ini dihubungkan dengan tubependek dengan uptake header atau riser (2) di ujung belakang.

Tube air (5) (diameter 100 mm ) dimiringkan dan menghubungkan uptake header ke downtake header. Tiap kolom (row) tube dihubungkan dengan 2 header, dan ada banyak kolom yang seperti itu. Header dibengkokkan jika dilihat dari arah tube sehingga satu tube tidak berada pada sela yang lainnya, dan gas panas bisa lewat dengan baik setelah memanasi semua tube. Header dilengkapi dengan lubang tangan di depan tube dan dilengkapi tutup(18).

Kotak Lumpur (6) disediakan pada tiap downtake header dan lumpur yang mengendap dipindahkan. Ada rantai kisi otomatis yang bergerak pelan pada tempat dimana batubara diumpankan dari hopper (21). Batu api penyangga menyebabkan gas panas bergerak ke atas dan ke bawah dan ke atas lagi sebelum meninggalkan cerobong asap Damper (17) di operasikan melaui sebuah rantai (22) lewat puli ke bagian depan boiler untuk mengatur aliran.

Boiler ini dipasang pada rangka-rangka besi, dan dikelilingi pada 4 sisinya oleh dinding batu api. Pintu (4) disediakan agar pekerja bisa masuk boiler untuk perbaikan dan pembersihan.

Air bersikulasi dari drum (1) ke header (2) dan melewati tube (5) ke header (3) dan kembali ke drum (1). Air bersikulasi terus sampai menguap. Sebuah pemanas lanjut uap terdiri dari banyak tube baja (10) dan berisi 2 kotak, 1 kotak uap panas lanjut (11) dan 1 kotak uap jenuh (12).

Uap dihasilkan diatas muka air dalam drum dan mengalir dalam pipa kering (13) dan lewat saluran masuk tube ke kotak uap panas lanjut (11). Uap ini kemudian melewati tube (10) ke kotak uap jenuh (12). Uap selama perjalanannya melewati tube (10), mengalami pemanasan lebih lanjut menjadi preheated. Uap kemudian diambil lewat saluran keluar pipa (14) ke katup pemberhenti/ stop valve (15).Boiler ini dipasang dengan perlengkapan standart, seperti katup keamanan (19), katuppengumpan (20) indikasi permukaan air (8) dan meter tekanan (9)It consists of a drum boiler steam and water drum (1). This drum is connected to the tubeuptake of short with a header or riser (2) at the back end.

Water Tube (5) (diameter 100 mm) tilted and connecting uptake downtake header to header. Each column (row) tube is connected with 2 header, and there are many fields like that. Header is bent when viewed from the direction of the tube so that one tube are not on the other sidelines, and hot gases can pass well after the heat all tubes. The header is equipped with a hand hole in front of the tube and fitted lid (18).

Mud Box (6) provided on each downtake header and mud to settle to be moved. There are automatic lattice chains moving slowly in places where coal is fed from the hopper (21). Flint buffer causes the hot gases move up and down and up again before leaving the chimney damper (17) operated through a chain (22) via pulleys to the front of the boiler to regulate the flow.

These boilers are mounted on the frame-iron frame, and is surrounded on four sides by stone walls of fire. Doors (4) are provided for workers to enter the boiler for repairs and cleaning.

Bersikulasi water from the drum (1) to the header (2) and through the tube (5) to the header (3) and returned to the drum (1). Water bersikulasi continue to evaporate. A further steam heating consists of many steel tube (10) and contains 2 boxes, 1 box of hot steam-up (11) and a saturated steam box (12).

Steam is produced above the water level in the drum and flows in the dry pipe (13) and through the inlet tube to further heat the steam box (11). This steam then passes through tube (10) into the saturated steam box (12). Steam during his travels through the tube (10), suffered further warming become preheated. Steam is then taken through the outlet pipe (14) into pemberhenti valve / stop valve (15).These boilers are fitted with standard equipment, such as the safety valve (19), valvefeeders (20) indicate surface water (8) and pressure meter (9)

Boiler La-mountBoiler ini adalah boiler uap tube air (water tube) tekanan tinggi modern dengan sirkulasi paksa. Sirkulasi dijaga oleh pompa centrifugal, yang digerakkan oleh turbin uap, memanfaatkan uap dari boiler.

Sirkulasi paksa menyebabkan air yang diumpankan dan bersikulasi lewat dinding air dan yang lewat drum sama dengan 10 kali massa uap yang menguap. Hal ini mencegah tube terpanaskan berlebihan.

Air umpan melewati ekonomiser ke drum penguapan. Kemudian ditarik ke pompa sirkulasi lewat tube. Pompa mengirim air umpan ke header pada tekanan diatas tekanan drum. Header membagikan air lewat nosel ke tube yang bekerja paralel. Air dan uap yang lewat tube ini menuju ke drum. Uap dalam drum kemudian disalurkan ke pemanas lanjutThese boilers are water tube steam boiler (water tube) modern high pressure with forced circulation. Circulation is maintained by a centrifugal pump, driven by steam turbines, using steam from the boiler.

Forced circulation of water causes the fed and bersikulasi passing through a wall of water and the drum is equal to 10 times the mass of vapor that evaporates. This prevents excessive tube is heated.

Ekonomiser feed water into the drum through evaporation. Then drawn into the pump circulation through the tube. Pumps send the water feed to the header at a pressure above the pressure drum. Header distribute water through the nozzle into the tube which works in parallel. Water and steam passing through this tube into the drum. Steam in the drum and then distributed to the heating-up

BOILER

I. PENDAHULUAN

Uap air yaitu gas yang timbul akibat perubahan fase air menjadi uap dengan cara pendidihan (boiling). Untuk melakukan proses pendidihan diperlukan energi panas yang diperoleh dari sumber panas, mislnya dari pembakaran bahan bakar (padat, cair, gas), tenaga listrik dan gas panas sebagai sisa proses kimia serta tenaga nuklir.

Sudah beribu-ribu tahun tahun manusia melakukan proses perebusan (boiling) air menjadi uap air, tetapi baru dua abad ini mereka baru menemui bagaimana untuk mempergunakan uap untuk kepentingan mereka yaitu dengan diciptakannya boiler. Boiler menghasilkan uap dan uap yang dihasilkan ini dapat dugunakan untuk membangkitkn listrik, menggerkkan turbin dan sebagianya.

II. KLASIFIKASI BOILER

Boiler pada dasarnya terdiri dari lumbung (drum) yan tertutup pada ujung pangkalnya dan dalam perkembangannya dilengkapi dengan pipa api maupun pipa air. Banyak orang mengklsifikasikan boiler tergantung pada sudut pandang masing-masing. Pada makalah ini boiler diklasifikasikan dalam kelas yaitu :

1. Berdasarkan fluida yang mengalir dalam pipa, maka boiler dikalsifikasikan sebagai :

a. Boiler pipa api (fire tube boiler)

b. Boiler pipa air (water tube boiler)

Pada boiler pipa api, fluida yang mengalir dalam adalah gas nyala (hasil pembakaran) yang membawa energi panas, yang segera mentransfernya ke air ketel melalui bidang pemanas.

Tujuan pipa-pipa api ini adalah untuk memudahkan distribusi panas kepada air ketel. Sedang untuk boiler pipa air fluida yang mengalir dalam pipa adalah air, energi panas yang ditransfer dari luar pipa (yaitu berasal dari ruang dapur/furnace) ke air ketel.

2. Berdasarkan pemakaiannya boiler dapat diklasifikasikan sebagai :

a. Ketel stasioner (stationer boiler) atau boiler tetap.

b. Boiler mobile atau disebut juga boiler portable.

Yang termasuk stasioner ialah boiler-boiler yang didudukan pada pondasi tetap seperti boiler untuk pembankit tenaga listrik, untuk industri dan sebagainya.

Yang termasuk boiler mobile ialah boiler yang dipasang pada pondasi yang dapat berpindah-pindah, seperti boiler lokomotif, boiler panjang dan sebagainya termasuk juga boiler pada kapal.

3. Berdasarkan letak dapur (furnace position), boiler diklasifikasikan sebagai :

a. Boiler dengan pembakaran di dalam (internal fired steam bolier) dalam hal ini dapur barada (pembakaran terjadi) di bagian dalam boiler. Kebanyakan boiler pipa api memakai sistem ini.

b. Boiler dengan pembakaran di luar (outernallyfired steam boiler), dalam hal ini dapur berada (pembakaran terjadi) di bagian luar boiler, kebanyakan boiler pipa air memakai sistem ini.

4. Menurut jumlah lorong (boiler tube), boiler diklasifikasikan sebagai :

a. Boiler dengan lorong tunggal (single tube steam boiler).

b. Boiler dengan loron ganda (multi tubuler steam boiler).

Pada single tube steam boiler, hanya terdapat satu lorong saja, apakah itu lorong api atau saluran air saja. Cornish boiler adalah single fire tube boiler dan simple vertical boiler adalah single water tube boiler.

Multi fire tube boiler misalnya boiler scotch dan multi water tube boiler misalnya boiler B dan W dan lain-lain.

5. Berdasarkan pada poros tutup drum (shell), boiler diklasifikasikan sebagi :

a. Boiler tegak (vertikal steam boiler), seperti boiler Cochran, boiler Clarkson dan sebagainya.

b. Boiler mendatar (horizontal steam boiler), seperti boiler Cornish, Lancashire, Scotch dan sebagainya.

6. Menurut bentuk dan letak pipa, boiler diklasifikasikan sebagai :

a. Boiler dengan pipa lurus, bengkok dan berlekak-lekuk (straight, bent and sinous tubuler heating surface)

b. Boiler dengan pipa miring-datar dan miring tegak.

7. Menurut sistem peredaran air boiler diklasifikasikan sebagai berikut :

a. Boiler dengan peredaran secara natural.

b. Boiler dengan peredaran paksa.

Pada boiler dengan perdaran secara natural air dalam boiler beredar/bersirkulasi secara alami, yaitu air yang ringan naik sedang air yang berat turun, sehingga terjadilah aliran konveksi alami. Umumnya Boiler beroperasi secara alami seperti boiler Lancarshire, Babcock & Wilcox dan lain-lain.

Pada boiler dengan sirkulasi paksa, aliran paksa diperoleh dari sebuah pompa centrifugal yang digerakkan dengan elektrik motor. Sistem aliran paksa biasanya dipakai pada boiler bertekanan tinggi.

8. Berdasarkan pada sumber panasnya untuk pembuatan uap, boiler diklasifikasikan 1. Boiler dengan bahn bakar alami 2. Boiler dengan bahan bakar buatan 3. Boiler dengan dapur listrik 4. Boiler dengan energi nuklir.

III. FUNGSI BOILER

Boiler berfungsi sebagai pesawat konversi energi yang mengkonversikan energi kimia (potensial) dari bahan bakar menjadi energi panas. Boiler terdiri dari dua komponen utama yaitu :

1. Dapur (furnace), sebagai alat untuk mengubah energi kimia menjad energi panas.

2. Alat penguap (eveporator) yang mengubah energi pembakaran (energi panas) menjadi energi potensial uap.

Kedua komponen tersebut di atas telah dapat untuk memungkinkan sebuah boiler untuk berfungsi. Sedangkan komponen lainnya adalah :

1. Corong asap dengan sistem tarikan gas asapnya, memungkinkan dapur berfungsi secara efektif. 2. Sistem perpipaan, seperti pipa api pada boiler pipa api, pipa air pad boiler pipa air memungkinkan sistem penghantaran kalor yang efektif antara nyala api atau gas panas dengan air boiler.

3. Sistem pemanas uap lanjut, sistem pemanas udara pembakaran serta sistem pemanas air pengisi boiler berfungsi sebagai alat untuk menaikan efisiensi boiler.

Agar sebuah boiler dapat beropersi dengan aman, maka perlu adanya sistem pengamanan yang disebut apendasi.

IV. APLIKASI BOILER PADA INDUSTRI PEMBANGKIT LISTRIK

Setelah kita mengetahui jenis dan tipe boiler serta fungsi boiler dan komponennya dari uraian di atas, maka akan menjadi lebih jelas lagi bagaimana cara kerja boiler dalam suatu sistem pembangkit listrik. Dalam makalah ini sistem yang kita ambil sebagai aplikasi contoh adalah sistem pada PLTU Paiton khususnya pada PT. YTL Jawa Timur

PROSES DASAR PRODUKSI LISTRIK

Di dalam PLTU batubara atau coal fired power plant , energi panas batubara dikonversikan ke dalam energi listrik dengan bantuan boiler , turbin dan generator. Batubara dari tempat penyimpanannya di bawa ke tempat penampungan batubara di area boiler setelah terlebih dahulu dihancurkan di ruangan penghancur batubara. Batubara tersebut kemudian disalurkan ke pengumpan batubara ( coal feeder ) yang dilengkapi alat pengatur aliran untuk dihaluskan pada mesin penghalus ( pulveriser atau coal mill ) sehingga dihasilkan tepung batubara yang halus. Batubara halus di dorong dengan udara panas yang dihasilkan dari Primary Air Fan dan dibawa ke pembakar batubara dengan cara di injeksikan ke ruang bakar boiler ( furnace ). Di sini tepung batubara yang keluar dari corner ( sudut – sudut boiler ) dibakar bersama- sama dengan udara panas dan api yang di injeksikan ke ruang bakar secara bersamaan. Udara panas yang masuk ke furnace dihasilkan dari fan yang disebut Forced Draft Fan , sedangkan api di hasilkan dari pemantik api atau ignitor.

Panas yang di hasilkan dari proses pembakaran ini melalui proses perpindahan panas secara konveksi akan mengubah air yang mengalir dalam pipa – pipa yang ada di dalam boiler menjadi uap jenuh ( saturated steam ) . Uap panas ini kemudian di panaskan lebih lanjut oleh super heater sampai menjadi uap panas kering ( dry super heated steam ) sehingga efisiensi boiler makin tinggi. Uap panas kering kemudian disalurkan ke turbin bertekanan tinggi dengan bantuan pipa – pipa tebal bertekanan tinggi dimana steam itu dikeluarkan lewat nozzle – nozzle mengenai baling –baling turbin. Saat mengenai baling – baling, energi kalor yang dimiliki steam akan berubah menjadi energi kinetik dan menggerakkan baling – baling turbin dan shaft turbin yang disambungkan dengan generator ikut berputar.

Shaft yang disambungkan dengan generator berupa silinder elektromagnetik besar sehingga ketika turbin berputar generator ikut berputar ,yaitu bagian rotor.Rotor generator tergabung dengan stator.Stator adalah bagian generator yang tidak ikut berputar , berupa gulungan yang menggunakan batang tembaga sebagai pendingin internal.Listrik dihasilkan dalam batang – batang tembaga stator dengan elektostatik di dalam rotor melalui putaran magnet. Listrik yang dihasilkan bertegangan 21 kV dan dengan trafo step up dinaikkan menjadi 500 kV , sesuai tegangan yang diminta PLN . Lihat gambar sistem pada lampiran .

BOILER MASTER SYSTEM

Coal fired power plant atau pembangkit listrik tenaga uap merupakan pembangkit listrik dengan menggunakan uap sebagai tenaga pembangkitnya.Untuk fungsi ini powerplant ini dapat dibagi menjadi dua bagian penting yaitu boiler master dan turbine master .Uap yang digunakan untuk pembangkit listrik ini dihasilkan dari proses perubahan wujud dari air ke uap yang dilakukan oleh boiler yang merupakan bagian dari boiler master .Sehingga boiler merupakan suatu komponen dalam power plant yang berfungsi untuk mengubah air menjadi uap melalui serangkaian proses yang kompleks dimana didalamnya terjadi perpindahan panas dan konversi energi dari kimia ke panas

Jenis boiler yang digunakan pada unit 5 dan 6 adalah tipe menggantung dengan pengontrol sirkulasi (controlled circulation) yaitu sirkulasi air dan uap pada boiler tidak terjadi secara natural tapi dipaksa dengan pompa BWCP ( Boiler water Circulating Pump) , hal ini memudahkan dalam pengoperasian boiler untuk menyesuaikan dengan kebutuhan air dan uap agar sesuai dengan beban yang diinginkan.Boiler ini didesain dengan satu kali proses pemanasan kembali (reheat) Boiler merupakan .suatu komponen besar yang terdiri dari komponen-komponen utama dan komponen pembantu agar dalam proses kerjanya mencapai efisiensi optimum.

Dalam pengoperasian boiler,ada beberapa parameter yang harus diperhatikan yaitu :

™ Aliran uap (Steam Flow )

Yaitu banyaknya uap yang harus dihasilkan boiler pada tingkat pengoperasian tertentu .Pengoperasian pada MCR (Maximum Continous Rating) merupakan pengoperasian boiler pada tingkat aliran uap maksimum yang bisa dijalankan secara berkelanjutan.Jika melebihi tingkat ini bisa merusak peralatan ataupun meningkatkan biaya perawatan.

Control Load untuk beban penuh aliran uap sekitar 48% dan sekitar 47 % untuk aliran uap pada tingkat MCR. Control load merupakan titik dimana suhu uap utama maupun uap pemanasan ulang telah mencapai titik desain kerjanya ( kondisi stabil )

™ Tekanan Boiler

Untuk mendapatkan energi yang sesuai dengan kebutuhan turbin agar dapt menggerakkan generator,maka tekanan uap panas kering yang dihasilkan pun harus sesuai dengan kebutuhan beban.Dalam hal ini ,tekanan uap dapat diatur melalui reheater dan superheater.

™ Temperatur Uap

Dalam proses konversi wujud dari cair menjadi uap,air perlu dipanaskan dalam furnace.Panas yang dihasilkan dari proses pembakaran dalam furnace tersebut juga harus diperhatikan agar suhu uap yang dihasilkan memenuhi standar yang ditentukan.Karena jika suhu uap kurang maka efisiensi akan turun tapi jika terlalu tinggi akan berpengaruh pada gas buangnya.

™ Efisiensi Boiler

Untuk melihat apakah desain suatu boiler telah tepat ditentukan oleh beberapa faktor yang mempengaruhi,diantaranya kegunaan unit boiler itu sendiri yaitu apakah uap yang harus dihasilkan konstan atau bervariasi sesuai kebutuhan generator pembangkit listrik. Selanjutnya yang menentukan juga adalah jenis dan kualitas bahan bakar yang akan dibakar : apakah padat,cair atau gas.Seberapa banyak uap harus dihasilkan tiap jamnya apakah ratusan atau bahkan jutaan pon tiap jamnya juga perlu dipertimbangkan dalam desain.

Pembentukan uap yang dipengaruhi penyerapan panas harus memenuhi setidaknya komponen berikut ini :

· Tekanan kerja tiap bagian dari boiler,hal ini penting untuk distribusi dan pemenuhan kebutuhan sistem dalam proses pengubahan air menjadi uap.

· Struktur power plant yang tepat untuk tipe proses pembakaran yang dipilih.

· Ukuran yang tepat dan pengaturan permukaan perpindahan panas untuk penyerapan panas saat proses pembakaran.

· Perlengkapan yang dibutuhkan selama proses .Alat untuk memasukkan udara, bahan bakar dan mengalirkan air.Piranti untuk memindahkan hasil pembakaran dan sistem pengendalian proses.

Permukaan penyerapam panas boiler dirancang untuk efisiensi dan biaya yang optimum agar empat tujuan dasar boiler tercapai yaitu :

1. Uap kering yang dihasilkan memilki tingkat kemurnian yang tinggi dalam keadaan apapun.

2. Pemanasan super terhadap uap kering sementara menjaga suhu tidak melebihi dari kondisi operasional boiler.

3. Pemanasan ulang terhadap uap yang tekanannya turun untuk digunakan kembali oleh turbin sementara menjaga suhu tidak melebihi dari kondisi operasional boiler.

4. Mengurangi suhu gas buang untuk meminimalkan rugi-rugi panas , mengendalikan korosi dan menghasilkan emisi yang tidak melebihi ketentuan.

Efisiensi termal adalah indikator seberapa baik kemampuan input panas boiler untuk menghasilkan uap pada suhu dan tekanan yang diminta. Adanya prinsip ekonomi dan biaya bahan bakar membuat powerplant harus beroperasi seefisien mungkin. Unit 5 dan 6 didesain dengan efisiensi 92,5 – 93,5 % tergantung kondisi operasional boiler ,pada MCR ,normal full load atau pada control load conditions.Untuk membandingkan performance boiler pada kondisi sekarang dengan kondisi desain awal nya ada tiga parameter yang bisa diperiksa.

® Fuel analysis

Analisa ini dilakukan untuk mengatuhi kandungan oksigen ,hidrogen dan karbon yang terdapat dalam bahan bakar yang digunakan.Karena kualitas bahan bakar dulu dengan sekarang bisa sangat berbeda.Perbedaan ini berpengaruh terhadap kebutuhan udara dan panas yang dilepaskan di ruang bakar ,begitu juga dengan massa aliran gas buang yang meninggalkan ruang bakar.

® Feedwater temperature

Perubahan suhu air yang masuk ke boiler menentukan tingkat pembakaran yang diperlukan di furnace ,lebih lanjut akan mempengaruhi panas yang dihasilkan dan banyaknya massa aliran.

® Excess Air

Banyaknya udara yang masuk ruang bakar berpengaruh terhadap jumlah panas yang dibawa dari furnace ( dry gas loss ) , banyaknya udara yang keluar merupakan faktor penting untuk menghitung efisiensi boiler.

Komponen Utama Boiler

Boiler dapat dikategorikan menjadi 2 macam berdasarkan segi konstruksinya, yakni boiler pipa api dan boiler pipa air.Jenis boiler yang digunakan di unit 5 dan 6 PLTU Paiton adalah boiler pipa air dimana fluida airnya berada dalam pipa sedangkan api atau gas hasil pembakaran berada di luar pipa.Tinggi bolier ini mencapai lebih kurang 60 meter yang dibagi menjadi tiga elevasi,dengan masing – masing corner pada tiap elevasinya terdapat 2 mill , 4 oil gun , 4 windbox dan ignitor.

Bahan bakar utama yang digunakan boiler adalah batubara, sedangkan solar hanya digunakan untuk pembakaran awal ketika start up dan apabila telah memenuhi temperatur yang dikehendaki maka diganti dengan batubara.Udara pembakaran diberikan oleh FD Fan setelah sebelumnya dipanaskan di Air Heater.Sedangkan ID Fan digunakan untuk menghisap dan mensirkulasikan gas buang dari furnace hingga ke stack sehingga tekanan dalam boiler adalah nol.

Pipa – pipa penguap air dalam boiler dipasang sedemikan rupa sehingga tersusun seperti dinding furnace.Pipa – pipa ini merupakan pipa panjang dengan ketebalan bervariasi pada sepanjang pipa.Pipa – pipa tersebut menerima panas secara radiasi.

Boiler ini dilengkapi dengan Steam Drum yang ditempatkan di luar furnace.Air pengisi pipa – pipa dalam furnace diperoleh dengan cara dipompa oleh Feed Water Pump (BWCP) dimana sebelumnya telah dipanaskan oleh High pressure heater dan Economizer . Kemudian Boiler Water Circulating Pump (BWCP) memompa air dari Steam Drum menuju Evaporator sehingga menjadi uap dan masuk ke dalam Steam Drum kembali.Dalam Steam Drum air dipisahkan dari uapnya, air yang telah dipisahkan akan disalurkan melalui Lowering Header yang ada di bawah tungku yang akan membagi air masuk ke pipa – pipa penguap (riser) yang tersusun di sekeliling dinding furnace.Pipa – pipa penguap yang ada pada dinding di bawah drum akan langsung bermuara pada Steam Drum, sementara yang ada pada dinding lainnya akan bermuara pada Steam Header (Tabung Pengumpulan Uap).

Dari Steam Header ini, uap basah yang terbentuk akan masuk ke Superheater, sedangkan yang masih berupa air akan disalurkan kembali melalui Down Comer dengan bantuan pipa.Uap yang dihasilkan setelah Superheater adalah uap kering yang disebut juga dengan Main Steam. Main Steam inilah merupakan uap yang siap digunakan untuk menggerakkan HP Turbine(High Pressure Turbine).Karena pada turbin ini mengalami ekspansi, maka temperatur dan tekanannya menurun sehingga pada keluaran HP Turbine terbentuk uap jenuh yang disebut Cold Steam.Uap jenuh ini tidak langsung disalurkan ke IP Turbine(Intermediate Pressure Turbine)., melainkan dipanaskan kembali di Reheater baru kemudian digunakan untuk menggerakkan IP Turbine.Uap keluaran dari IP Turbine dialirkan ke LP Turbine (Low Pressure Turbine)1 dan 2.Lebih jelas tentang siklus yang dijelaskan diatas pada gambar 1 water steam cycle lampiran .

Dalam kejadian dilapangan beban operasional boiler tidak selalu konstan tapi bervariasi sesuai permintaan konsumen.Untuk mengatasi hal ini maka saat boiler mengalami perubahan beban, ada beberapa komponen yang harus disesuaikan agar uap yang dihasilkan seimbang.

Saat ada perintah untuk mengubah beban,maka secara otomatis perintah penyesuaian itu disampaikan ke boiler master agar komponen yang termasuk didalamnya bisa menyesuaikan sehingga rasio udara dan bahan bakar stabil . Diantaranya jika beban boiler berubah maka kapasitas bahan bakar berubah yaitu dengan mematikan atau menghidupkan mill pada elevasi tertinggi secara bertahap. Selain itu,perubahan juga diikuti oleh serangkaian alat pendukungnya ,misalnya pengaturan udara pembakaran oleh FD fan,pengaturan posisi naik turun windbox untuk mendapat bola api yang diinginkan dan lain sebagainya.

Adapun bagian utama yang menyusun Boiler adalah sebagai berikut :

1. Economizer

Berfungsi untuk memanaskan air setelah melewati High Pressure Heater.Pemanasan dilakukan dengan memanfaatkan panas dari flue gas yang merupakan sisa dari pembakaran dalam furnace.

Temperatur air yang keluar dari Economizer harus dibawah temperatur jenuhnya untuk mencegah terjadinya boiling dalam Economizer.Karena perpindahan panas yang terjadi dalam Economizer merupakan konveksi, maka menaikkan luas permukaan akan mempermudah perpindahan panas ke air.Inilah sebabnya mengapa desain pipa Economizer dibuat bertingkat .

Keuntungan:

· Meningkatkan efisiensi unit karena dengan memanfaatkan kalor flue gas untuk memanaskan air, dapat mengurangi kebutuhan kalor yang besar untuk pemanasan air sampai terbentuk uap kering pada Superheater.

· Biaya Operasi lebih ekonomis karena jumlah bahan bakar untuk pemanasan pada Superheater menjadi lebih sedikit.

· Maintenance Cost dapat dihemat karena dengan adanya Economizer, thermal shock pada pipa boiler dapat dihindari.

Kerugian :

· Desain pipa yang bertingkat akan menimbulkan masalah abu, terutama bila batubara yang digunakan kadar abunya tinggi.

2. Superheater

Berfungsi untuk memanaskan uap dari Steam Drum menjadi uap panas lanjut (main steam).Main steam digunakan untuk melakukan kerja dengan ekspansi dalam turbin.

Superheater memiliki lima bagian utama, yaitu :

1. Superheater (SH) Vertical Platens

2. SH Division Panel

3. Low Temperature SH Pendant

4. Low Temperature SH Horizontal

5. Back Pass and Roof

3. Reheater

Berfungsi untuk memanaskan kembali uap yang telah mengalami ekspansi dalam turbin.Uap keluaran turbin berupa cold steam sehingga perlu dipanaskan kembali dan dimasukkan kembali ke dalam Boiler . Reheater kemudian memasuki Front Reheater dan keluar melalui Reheater Vertical Spaced Front Outlet Header menuju IP Turbine.

4. Main Steam Drum

Fungsi utamanya adalah untuk memisahkan uap dari campuran air dan uap yang masuk ke steam drum .Selain itu juga berfungsi untuk mendistribusikan feedwater,membuang kontaminan dari air boiler , menambahkan bahan kimia, dan mengeringkan uap setelah dipisahkan dari air. Uap berada pada bagian atas bejana dan air berada pada bagian bawah.Air dari Steam Drum disalurkan ke Evaporator dengan cara dipompa oleh BWCP.

Uap dan air dalam steam drum dipisahkan dengan tiga tahap,primary , secondary dan drying . Tahap primary dan secondary dilakukan oleh turbo separator dan plat yang berombak – ombak melakukan tahap drying.Fungsi utama dari alat pemisah ini adalah untuk memindahkan uap dari air boiler dan untuk mengurangi campuran yang terdapat dalam uap sebelum meninggalkan steam drum.

5. Down Comer

Merupakan saluran air dari Steam Drum ke Header (Pengaman) yang berada di bawah ruang bakar dimana dari header butir – butir air panas akan dipanaskan melalui pipa – pipa yang tersusun di dinding furnace.Pada Down Comer bagian bawah terdapat suatu pompa yang disebut dengan Boiler Water Circulating Pump (BWCP) yang digunakan untuk mengatur sirkulasi air yang akan dipanaskan atau diuapkan.Ada enam downcomer dengan O.D.16” ( 406.4 mm).

6. Furnace

Merupakan ruang bakar yang pada dindingnya tersusun pipa – pipa.

7. Blow Down

Untuk mengontrol kualitas air serta mengurangi kandungan zat padat (Silika) dalam air sehingga tidak terbentuk kerak hangus pada furnace. Alat ini akan bekerja secara otomatis saat sensor menunjukkan kandungan silika dalam air melebihi standar.Ia akan membuang sebagian kecil air dari drum ( 1 % sampai 2 % dari tingkat penguapannya)

BOILER

I. INTRODUCTION

Water vapor is the gas resulting from the phase change water into steam by boiling (boiling). To make the process of boiling heat energy required is obtained from a heat source, mislnya from burning fuel (solid, liquid, gas), electric power and heat as the rest of the process gas chemistry and nuclear power.

Already thousands of years of human conduct boiling water (boiling) water into water vapor, but only two of this century they've met how to use the steam for their interests by the creation of the boiler. Boilers produce steam and the steam produced can be used for electricity membangkitkn, menggerkkan turbine and sebagianya.

II. BOILER CLASSIFICATION

Boiler basically consists of the barn (drums) yan closed at the end of the base and in its development pipeline is equipped with fire and water pipes. Many people mengklsifikasikan boiler depending on their respective viewpoints. In this paper boilers are classified in the class are:

1. Based on the fluid flowing in the pipe, the boiler dikalsifikasikan as:

a. Fire tube boilers (fire tube boiler)

b. Boiler water pipe (water tube boilers)

In a fire tube boilers, the fluid flowing in the gas flame (combustion), which carry heat energy, which immediately transfer them to the boiler water through the heating field. The purpose of the fire pipes is to facilitate the distribution of heat to the water kettle. As for the water pipe boiler fluid flowing in pipes is water, heat energy is transferred from outside the pipe (ie coming from the kitchen / furnace) into the water kettle.

2. Based on its use boilers can be classified as:

a. The kettle is stationary (stationary boiler) or a fixed boiler.

b. Mobile boiler or boiler also called portable.

Which includes stationary boiler-boiler is didudukan on permanent foundations such as boilers for electric power pembankit, for industry and so forth.

Which includes a mobile boiler boiler is mounted on a foundation that can be moved, such as locomotive boiler, boiler and so long as well as the boiler on the ship.

3. Based on the location of the kitchen (furnace position), the boiler is classified as:

a. Boilers with combustion in (internally fired steam bolier) in this kitchen Barada (combustion occurs) on the inside of the boiler. Most of the fire tube boilers using this system.

b. Boiler by burning out (outernallyfired steam boilers), in this case the kitchen was (burning occurs) on the outside of the boiler, water tube boilers mostly use this system.

4. According to the number of alley (boiler tubes), the boiler is classified as:

a. Boilers with a single aisle (single tube steam boilers).

b. Boiler with Loron double (multi tubular steam boilers).

In the single tube steam boilers, there is only one aisle, whether it is the channel tunnel fire or water. Cornish boiler is a single fire tube boilers and simple vertical water tube boiler is a single boiler.

Multi boiler fire tube boilers eg scotch and multi water tube boilers for example the boiler B and W and others.

5. Based on the drum shaft cap (shell), boiler classified as:

a. Boiler upright (vertical steam boilers), such as Cochran boiler, boiler Clarkson and so on.

b. Boiler landscape (horizontal steam boilers), such as boilers Cornish, Lancashire, Scotch, and so forth.

6. According to the shape and location of pipes, boilers are classified as:

a. Boiler with straight pipes, bent and berlekak-dent (straight, bent and sinous tubular heating surface)

b. Tilt-tube boiler with flat and upright tilt.

7. According to the boiler water circulation systems are classified as follows:

a. Boilers with natural circulation.

b. Boilers with forced circulation.

In boilers with natural perdaran water in the boiler supply / circulating in nature, ie water is water that rises a light weight down, so there was a natural convection flow. Boilers generally operate naturally as Lancarshire boilers, Babcock & Wilcox and others.

In the boiler with forced circulation, forced flow is obtained from a centrifugal pump driven by electric motors. Forced flow system is usually used on high pressure boilers.

8. Based on the source of heat for making steam, boiler classified 1. Boilers with natural gas Bahn 2. Boiler with artificial fuel 3. Boiler with electric kitchen 4. Boiler with nuclear energy.

III. FUNCTION BOILER

Boilers serves as a plane of energy conversion that converts chemical energy (potential) of fuel into heat energy. Boiler consists of two main components namely:

1. Kitchen (furnace), as a tool to convert chemical energy menjad heat energy.

2. Vaporizer (eveporator) that converts combustion energy (heat energy) into potential energy of steam.

The two components mentioned above have been able to allow a boiler to function. While the other components are:

1. Flue gas system with the pull of smoke, allowing the kitchen to function effectively. 2. Piping systems, such as pipeline fire in the fire tube boiler, water pipe water pipe boiler pad enables the effective delivery systems of heat between the gas flame or hot water boiler. 3. Advanced steam heating system, combustion air heating systems and filling water boiler heating system to function as a tool to raise the efficiency of the boiler.

In order for a boiler to be operating safely, it is necessary to the security system called apendasi.

IV. BOILER APPLICATIONS IN ELECTRIC POWER INDUSTRY

Once we know the kinds and types of boilers and boiler functions and components of the above description, it will become clearer how the workings of the boiler in a power system. In this paper we take the system as an application example is a system in Paiton especially at PT. YTL East Java

BASIC ELECTRICITY PRODUCTION PROCESS

In the coal power plant or coal fired power plants, coal thermal energy converted into electrical energy with the help of a boiler, turbine and generator. Coal from storage in coal brought to the shelter in the area of the boiler after the first was destroyed in the coal crusher room. Coal is then channeled into the

feeder coal (coal feeder) equipped with flow regulator device for mashing the engine penghalus (pulveriser or coal mill) to produce the fine coal powder. Fine coal driven by hot air generated from the Primary Air Fan and taken to burning coal in a way in injected into the boiler combustion chamber (furnace). Here the coal powder that comes out from the corner (the corner - the corner of the boiler), burnt together with hot air and fire in injected into the combustion chamber simultaneously. The hot air entering the furnace resulting from the fan who called Forced Draft Fans, while the fire is derived from the cigarette lighter or ignitor.

Heat generated from the combustion process is through a process of heat transfer by convection will change the water flowing in the pipe - pipe that is in the boiler becomes saturated steam (saturated steam). Steam heat is then cooked further by the super hot steam heater until it becomes dry (dry super-heated steam) so that the higher the boiler efficiency. Dry hot steam and then distributed to high-pressure turbine with the help of pipes - thick high-pressure pipe which steam is expelled through the nozzle - the nozzle of the turbine blades. When the blades - blades, which is owned steam heat energy turns into kinetic energy and move the propeller - the turbine blades and turbine shaft which is connected to the generator rotating part.

Shaft which is connected to the generator in the form of large electromagnetic cylinder so that when the turbine rotates the generator rotating part, which is part rotor.Rotor stator.Stator generator is incorporated with the generator which are not spin, a roll that uses copper rod as produced in the rod cooling internal.Listrik - copper rod inside the stator with elektostatik magnet rotor through a rotation. Electricity generated voltage 21 kV and with step-up transformer is increased to 500 kV, according to the required voltage PLN. See the picture on the attachment system.

BOILER MASTER SYSTEM

Coal fired power plant or steam power plant is generating electricity by using steam as a power powerplant pembangkitnya.Untuk this function can be divided into two important parts of the boiler and turbine master's master. Steam is used to generate electricity is generated from the process of changing the form of water into steam by a boiler which is part of the boiler master. So the boiler is a component in a power plant which is used to convert water into steam through a series of complex processes in which the activities occurring in heat transfer and conversion of chemical energy into heat

Type of boiler used in the units 5 and 6 are the type to hang with circulation control (controlled circulation) is the circulation of water and steam in the boiler does not occur naturally but was forced to pump BWCP (Boiler water circulating pump), it is easier to adjust the boiler operating with water and steam needs to be consistent with diinginkan.Boiler load is designed with a one-time re-heating process (reheat) Boiler is. a major component of the main components and auxiliary components for the working process to reach optimum efficiency.

In the operation of the boiler, there are several parameters that must be considered are:

™ The flow of steam (Steam Flow)

Which is the number of steam boilers must be produced at a certain level of operation. Operation of the MCR (Maximum Continuous Rating) is a boiler operating at maximum steam flow rate that can be done in berkelanjutan.Jika exceeding this level could damage the equipment or increase the cost of care.

Control Load to full load steam flow of about 48% and about 47% for steam flow at MCR. Control RNA is the point where the main steam temperature and steam reheating has reached its design point (stable condition)

™ Pressure Boilers

To get the energy needs for dapt turbine generator, the vapor pressure of dry heat generated must be in accordance with the needs beban.Dalam this case, the vapor pressure can be regulated through the reheater and superheater.

™ Temperature Steam

In the process of conversion from liquid to vapor form, water needs to be heated in furnace.Panas resulting from the combustion process in the furnace should also be noted that the temperature of the steam produced to meet the standards ditentukan.Karena if vapor temperature is less then the efficiency will go down but if too high will affect the gas dump.

Boiler Efficiency ™

To see if the proper design of a boiler has been determined by several factors which affect, among utility boiler unit itself is whether the steam to be generated constant or varies according to the needs of generators. Furthermore, that determines also the type and quality of fuel to be burned: whether solid, liquid or gas.Seberapa much steam must be generated every hour whether hundreds or even millions of pounds every hour will also need to be considered in the design.

Influenced the formation of steam heat absorption must meet at least the following components:

· Working pressure of each section of the boiler, it is important for distribution and fulfillment systems in the process of changing water into steam.

· Power plant structure appropriate for the selected type of combustion process.

· Size right and setting the heat transfer surface for heat absorption during the combustion process.

· Equipment needed during the process. Tools to include air, fuel and drain air.Piranti to move the combustion products and process control systems.

Penyerapam surface heat boilers are designed for optimum efficiency and cost for four basic purposes boiler is achieved, namely:

1. The resulting dry steam has a high purity level under any circumstances.

2. Super heating of steam dry while keeping the temperature does not exceed the operational condition of the boiler.

3. Reheating of the steam pressure is down for reuse by the turbines while maintaining the temperature does not exceed the operational condition of the boiler.

4. Reduce exhaust gas temperature to minimize heat loss, corrosion control and produce emissions that do not exceed the provisions.

Thermal efficiency is an indicator of how well the boiler heat input capacity to produce steam at temperatures and pressures required. The existence of economic principles and the cost of fuel makes powerplant must operate as efficiently as possible. Units 5 and 6 are designed with efficiency from 92.5 to 93.5% depending on boiler operating conditions, the MCR, the normal full load or on load control conditions.Untuk compare performance of boilers at present condition with his original design conditions there are three parameters that can be checked .

® Fuel analysis

This analysis is done to mengatuhi content of oxygen, hydrogen and carbon contained in fuel quality fuel digunakan.Karena past and present can be very berbeda.Perbedaan is impacting on the needs of air and heat released in combustion chamber, as well as the mass of the gas flow exhaust leaving the combustion chamber.

® feedwater temperature

Changes in water temperature entering the boiler to determine the necessary level of combustion in the furnace, will further affect the heat produced and the number of mass flow.

® Excess Water

Number of air entering the combustion chamber effect on the amount of heat carried from the furnace (dry gas loss), the number of air that comes out is an important factor to calculate the boiler efficiency.

Main Components Boilers

Boilers can be categorized into 2 types based on the terms of its construction, the fire tube boilers and boiler tube boiler air.Jenis used in units 5 and 6 Paiton is a water pipe boiler where the water is fluid in the pipe while the gas flame or combustion products are outside the pipe . High bolier reaches approximately 60 meters which is divided into three elevation, with each - each corner on each elevation there are 2 mill, 4 gun oil, 4 windbox and ignitor.

The main fuels used in boilers is coal, while solar is only used for initial combustion when the start up and when it meets the desired temperature then replaced with batubara.Udara combustion is given by the FD fan after being heated at Air Heater.Sedangkan ID Fan is used to suck and circulate the exhaust gas from the furnace to the stack so that the pressure in the boiler is zero.

Pipes - pipe vaporizer water in the boiler installed in such a way that made up like a wall furnace.Pipa - this pipe is a long pipe with thickness varies along pipa.Pipa - pipe receives heat radiation.

It is equipped with a Steam Boiler Drum placed outside furnace.Air filler pipe - pipe in the furnace is obtained by pumping by Feed Water Pump (BWCP) which previously had been heated by the high pressure heater and economizer. Then the circulating Water Boiler Pump (BWCP) pumping water from the steam drum to the evaporator so that the steam and into the Steam Drum Steam Drum kembali.Dalam separated from water vapor, water that has been separated will be channeled through

the lowering of existing header in the bottom of the furnace that will divide the water into the pipe - pipe vaporizer (riser) are arranged around the walls furnace.Pipa - vaporizer pipe that is on the wall below the drum will directly lead to the Steam Drum, while the other is on the wall will lead to the Steam Header (Collection Tubes Steam).

Steam Header From this, wet steam formed will go to the superheater, while still in the form of water will be channeled back through the Down Comer with the help pipa.Uap produced after a dry steam superheater is also called the Main Steam. Main Steam is a vapor that is ready to be used to drive the HP Turbine (High Pressure Turbine). Because the turbine is expanded, then the temperature and pressure is decreased so that at the output of the HP Turbine saturated vapor formed the so-called Cold Steam.Uap saturation is not directly distributed to Turbine IP (Intermediate Pressure Turbine)., but back in Reheater heated and then used to drive the output of the IP IP Turbine.Uap flowed to LP Turbine Turbine (Low Pressure Turbine) 1 and 2.Lebih clear about the cycle described above in Figure 1 water-steam cycle attachment.

In the event the field of boiler operating load is not always constant but varies according to demand konsumen.Untuk cope with this so when the boiler load changes, there are several components that must be adjusted so that the steam produced balanced.

Currently there are commands to change the load, then automatically adjusting command was delivered to the boiler master for components that can adjust so that includes air and fuel ratio is stable. Among them, if boiler load changes, it changes the fuel capacity is to turn off or turn on the mill at the highest elevation gradually. In addition, changes also followed by a series of supports, such as combustion air setting by the FD fan, setting the position up and down windbox to get the desired ball of fire and so forth.

The main parts that make up the boilers are as follows:

1. Economizer

Serves to heat the water after passing through the High Pressure Heater.Pemanasan done by using heat from flue gases which is the remainder of the combustion in the furnace.

The temperature of water coming out of the economizer must be below its saturation temperature to prevent boiling in Economizer.Karena heat transfer that occurs in a convection economizer, then increasing the surface area will facilitate the transfer of heat into air.Inilah why economizer pipe design is made bunk.

Advantages:

Improve efficiency of the unit due to the use of flue gas heat to heat water, can reduce the need for large heat for heating the water to dry steam formed in the superheater.

· Cost Surgery is more economical because the amount of fuel for heating in the superheater becoming fewer.

· Maintenance Cost savings due to the economizer, thermal shock on the boiler tube can be avoided.

Disadvantages:

· Design stratified pipe ash will cause problems, especially if coal is used high ash content.

2. Superheater

Serves to heat the steam from the steam drum into the steam heat-up (main steam). Main steam is used to do work with the expansion in the turbine.

Superheater has five main sections, namely:

1. Superheater (SH) Vertical Platens

2. SH Division Panel

3. Low Temperature SH Pendant

4. Low Temperature: SH Horizontal

5. Back Pass and Roof

3. Reheater

Serves to reheat the steam that has undergone expansion in output turbin.Uap form of cold steam turbine that needs to be heated again and put back into the boiler. Front Reheater Reheater then enter and exit through Reheater Vertical Front Outlet Header spaced toward IP Turbine.

4. Main Steam Drum

Its main function is to separate the steam from a mixture of water and steam entering the steam drum. It also serves to distribute feedwater, remove contaminants from the water boiler, adding chemicals, and dry steam after being separated from the water. Steam is at the top of the vessel and the water is at the bawah.Air of Steam Drum channeled into the evaporator is pumped by BWCP manner.

Steam and water in the steam drum are separated by three stages, primary, secondary and drying. Primary and secondary stages performed by turbo separators and plate are choppy - the waves do drying.Fungsi main stage of the separator is to remove water vapor from the boiler and to reduce the mixture contained in the steam before leaving the steam drum.

5. Down Comer

Is a water channel from the Steam Drum to the Header (Safety) under which the combustion chamber of the header item - item to be heated by hot water pipes - pipes that made up the wall furnace.Pada Comer Down the bottom there is a pump called the Boiler Water circulating Pump (BWCP) used to regulate the circulation of water to be heated or diuapkan.Ada six downcomer with OD16 "(406.4 mm).

6. Furnace

Is the combustion chamber walls are composed of the pipe - the pipe.

7. Blow Down

To control water quality and reduce the solids content (silica) in water so as not to scorch the crust formed on the furnace. This device will work automatically when sensors indicate the content of silica in water exceeds standar.Ia will remove a small portion of water from the drum (1% to 2% of the rate of evaporation)

Metode yang paling umum adalah penganalisis oksigen secara sinambung

dengan pembacaan langsung ditempat, dimana operator dapat menyetel aliran udara. Penurunan lebih lanjut

10–15% dapat dicapai melebihi sistem sebelumnya.

Alat analisis oksigen sinambung yang sama dapat memilikipneumatic

damper positioner yang dikedalikan dengan alat pengendali jarak jauh,

dimana pembacaan data tersedia di ruang kendali. Hal ini membuat operator mampu mengendalikan sejumlah

sistem pengapian dari jarak jauh secara serentak.

Sistem yang paling canggih adalah pengendaliandamper cerobong otomatis, yang karena harganya hanya diperuntukkan bagi sistem yang besar. 4.6 Penghindaran kehilangan panas radiasi dan konveksi

Permukaan luarshe ll boiler lebih panas daripada sekitarnya. Jadi, permukaan melepaskan panas ke lingkungan

tergantung pada luas permukaan dan perbedaan suhu antara permukaan dan lingkungan sekitarnya.

Panas yang hilang darishe ll boiler biasanya merupakan kehilangan energi yang sudah tertentu, terlepas dari

keluaran boiler. Dengan rancangan boiler yang modern, kehilangan ini hanya 1,5 persen dari nilai kalor kotor

pada kecepatan penuh, namun akan meningkat ke sekitar 6 persen jika boiler beroperasi hanya pada keluaran

25 persen.

Perbaikan atau pembesaran isolasi dapat mengurangi kehilangan panas pada dinding boiler dan pemipaan. 4.7 Pengendalianblowdown secara otomatis Blowdown kontinyu yang tidak terkendali sangatlah sia-sia. Pengendali blowdown otomatis dapat dipasang yang merupakan sensor dan merespon pada konduktivitas air boiler dan pH.Blowdown 10 persen dalam boiler 15 kg/cm2 menghasilkan kehilangan efisiensi 3 persen. 4.8 Pengurangan pembentukan kerak dan kehilangan jelaga

Pada boiler yang berbahan bakar minyak dan batubara, jelaga yang terbentuk pada pipa-pipa bertindak sebagai

isolator terhadap perpindahan panas, sehingga endapan tersebut harus dihilangkan secara teratur. Suhu

cerobong yang meningkat dapat menandakan pembentukan jelaga yang berlebihan.

Hasil yang sama juga akan terjadi karena pembentukan kerak pada sisi air. Suhu gas keluar yang tinggi pada

udara berlebih yang normal menandakan buruknya kinerja perpindahan panas. Kondisi ini dapat diakibatkan

dari pembentukan endapan secara bertahap pada sisi gas atau sisi air. Pembentukan endapan pada sisi air

memerlukan sebuah tinjauan pada cara pengolahan air dan pembersihan pipa untuk menghilangkan endapan.

Diperkirakan kehilangan efisiensi 1 persen terjadi pada setiap kenaikan suhu cerobong 22°C.

Suhu cerobong harus diperiksa dan dicatat secara teratur sebagai indikator pengendapan jelaga. Bila suhu gas

meningkat ke sekitar 20°C diatas suhu boiler yang baru dibersihkan, maka waktunya untuk membuang

endapan jelaga. Oleh karena itu direkomendasikan untuk memasang termometer jenis

dial pada dasar cerobong untuk memantau suhu gas keluar cerobong.

Diperkirakan bahwa 3 mm jelaga dapat mengakibatkan kenaikan pemakaian bahan bakar sebesar 2,5 persen

disebabkan suhu gas cerobong yang meningkat. Pembersihan berkala pada permukaan tungkuradian t, pipa-

pipa boiler, economizers dan pemanas udara mungkin perlu untuk menghilangkan endapan yang sulit

dihilangkan tersebut.

4.9 Pengurangan tekanansteam pada boiler

Hal ini merupakan cara yang efektif dalam mengurangi pemakaian bahan bakar, jika diperbolehkan, sebesar 1

hingga 2 persen. Tekanansteam yang lebih rendah memberikan suhusteam jenuh yang lebih rendah dan tanpa

pemanfaatan kembali panas cerobong, dimana dihasilkan penurunan suhu pada gas buang.

Steam dihasilkan pada tekanan yang sesuai permintaan suhu/tekanan tertinggi

untuk proses tertentu. Dalam beberapa kasus, proses tidak beroperasi sepanjang waktu dan terdapat jangka

waktu dimana tekanan boiler harus diturunkan. Namun harus diingat bahwa penurunan tekanan boiler akan

menurunkan volum spesifiksteam dalam boiler,dan secara efektif mende- aerasi keluaran boiler. Jika

bebansteam melebihi keluaran boiler yang terdeaerasi, pemindahan air akan terjadi. Oleh karena itu, manajer

energi harus memikirkan akibat yang mungkin timbul dari penurunan tekanan secara

hati- hati, sebelum merekomendasikan hal itu. Tekanan harus dikurangi secara bertahap, dan harus

dipertimbangkan tidak boleh lebih dari 20 persen penurunan.

4.10 Pengendalian kecepatan variabel untukfan,blower dan pompa

Pengendali kecepatan variabel merupakan cara penting dalam mendapatkan penghematan energi. Umumnya,

pengendalian udara pembakaran dipengaruhi oleh klep penutupdamper yang dipasang pada fan forced dan

induced draft. Dampers tipe terdahulu berupa alat kendali yang sederhana,

kurang teliti, memberikan karakteristik kendali yang buruk pada kisaran operasi atas dan bawah. Umumnya,

jika karakteristik beban boiler bervariasi, harus dievaluasi kemungkinan menggantidamper dengan VSD.

4.11 Pengendalian beban boiler

Efisiensi maksimum boiler tidak terjadi pada beban penuh akan tetapi pada sekitar dua pertiga dari beban

penuh. Jika beban pada boiler berkurang terus maka efisiensi juga cenderung berkurang. Pada keluaran nol,

efisiensi boilernya nol, dan berapapun banyaknya bahan bakar yang digunakan hanya untuk memasok

kehilangan-kehilangan. Faktor-faktor yang mempengaruhi efisiensi boiler adalah:

Ketika beban jatuh, begitu juga halnya dengan nilai laju aliran massa gas

buang yang melalui pipa-pipa. Penurunan dalam laju alir untuk area perpindahan panas yang sama mengurangi

suhu gas buang keluar cerobong dengan jumlah yang kecil, mengurangi kehilangan panas

sensible. Beban dibawah separuhnya, hampir kebanyakan peralatan pembakaran

memerlukan udara berlebih yang lebih banyak untuk membakar bahan bakar secara sempurna. Hal ini meningkatkan kehilangan panas sensible. Umumnya, efisiensi boiler berkurang dibawah 25 persen laju beban dan operasi boiler dibawah tingkatan ini harus dihindarkan sejauh mungkin. 4.12 Penjadwalan boiler yang tepat Karena efisiensi optimum boiler terjadi pada 65-85 persen dari beban penuh, biasanya akan lebih efisien, secara keseluruhan, untuk mengoperasikan

lebih sedikit boiler pada beban yang lebih tinggi daripada mengoperasikan dalam jumlah banyak pada beban yang rendah. 4.13 Penggantian boiler

Potensi penghematan dari penggantian sebuah boiler tergantung pada perubahan yang sudah diantisipasi pada

efisiensi keseluruhan. Suatu perubahan dalam boiler dapat menarik secara finansial jika boiler yang ada:

Tua dan tidak efisien

Tidak mampu mengganti bahan bakar yang lebih murah dalam

pembakarannya Ukurannya melampaui atau dibawah persyaratan yang ada

Tidak dirancang untuk kondisi pembebanan yang ideal

Studi kelayakan harus menguji seluruh implikasi bahan bakar jangka panjang dan rencana pertumbuhan

perusahaan. Harus dipertimbangkan seluruh faktor keuangan dan rekayasa. Karenaplant boiler secara

tradisional memiliki umur pakai lebih dari 25 tahun, penggantian harus dipelajari secara hati-hati.

5. Perancangan boiler

Boiler yang kami gunakan dalam perancangan pabrik metanol dari gas alam yaitu tipe fire tube

boiler. Alasan pemilihan boiler ini yaitu tekanan operasinya kecil dan bahan bakar yang digunakan adalah fuel

gas. Perancangan

fire tube boiler dapat dilihat dibawah ini. UNEP, 2006,

http://www.energyefficiencyasia.org/docs/ee_modules/indo/Chap

Understanding boiler According to UNEP (2006), A boiler is a closed vessel where the heat combustion poured into hot water until the water formed atausteam. Hot water or at a certain pressure steam is then used for transferring heat to

a process. Water is a useful and inexpensive medium for transferring heat to a process. If the water is boiled until menjadisteam, volumnya will increase by approximately 1,600 times, producing a force that explosive gunpowder, so the boiler is the equipment that must be managed and maintained very well.

Boiler system consists of: feed water systems, sistemsteam and fuel system. Water system provides water to the boiler automatically according to kebutuhansteam. Various valves are provided for purposes of maintenance and repair. Sistemsteam collect and control produksisteam in boiler.Steam flowed through the system

pipelines to the point of the user. In the overall system, tekanansteam regulated using valves and monitored with pressure monitoring devices. Fuel system is all the equipment used to provide fuel to produce the required heat. The equipment needed in the fuel system depends on the type of material fuel used in the system.

The water supplied to the boiler to be changed menjadisteam called feed water. Two sources of feed water are: (1) condensate that condenses atausteam who returned from the process and (2) Airmakeup (treated raw water) which must come from outside the boiler room danplant process. To obtain a higher efficiency boiler, digunakaneconomizer to preheat the feed water using waste heat in flue gases. 2.Tipe-type boilers Boilers consist of different types namely: 1.Fire Tube Boiler

In fire tube boiler, hot gases pass through pipe - pipe and boiler feed water is inside the shell to be changed menjadisteam. Fire tube boilers are usually used to kapasitassteam tekanansteam relatively small with low to moderate. As a guideline, fire tube boilers kecepatansteam competitive for up to 12,000 kg / h with pressure to 18 kg/cm2. Fire tube boiler using fuel oil, gas or solid fuel in its operations. For economic reasons, most fire tube boiler is constructed as a "package" boilers (assembled by the manufacturer) for all fuels. Figure 1. Fire Tube Boilers 2.Water Tube Boiler In water tube boilers, boiler feed water flowing through the pipe - pipe in. into the drum. Water is heated by gas burners tersikulasi form

steam in the steam in the drum. These boilers are selected if the need steamdan tekanansteam high as in the case of boilers for power generation. Water tube boilers are very modern designed with a capacity steamantara

4500-12000 kg / hr, with very high pressure. Many water tube boilers that are constructed in the package when used fuel oil and gas. For water tube boilers using solid fuel, is not commonly designed package. Characteristics of water tube boiler as follows: • Forced, induceddan balanced draft helped to improve efficiency burning • Less tolerant of water quality produced water treatment dariplant • Allows for thermal efficiency levels higher Figure 2.Water Tube Boiler 3. Package Boiler

The packaged boiler because it was available as a complete package. When sent to the factory, requiring only pipasteam, plumbing, fuel supply and electrical connections to operate. Package boilers are generally tipeshell andtube with fire tube design with good heat transfer of high radiation and convection. The characteristics of packaged boilers are:

The small combustion chamber and heat is released to produce high more rapid evaporation.

A large number of small diameter pipe to make a convective heat transfer is good.

Sistemf o rc ed or induced draft combustion efficiency is good. A number of passes / pass resulted in overall heat transfer

better. thermal efficiency levels higher than denganboiler

other.

Boilers were grouped by jumlahpass / path is the number of times through the combustion gas boiler. Combustion chamber was placed as the first track after the later one, two, or three sets of pipe fire. Boiler most common in this class are units tigapass / path with two setfire-tube/pipa flame and exhaust gases exiting from the back boiler. Figure 3. Package Type Boiler 3 Pass, fuel oil 4. With Fluidized Bed Combustion Boilers (FBC)

Fluidized bed combustion (FBC) has emerged as a viable alternative and has significant advantages compared to conventional combustion systems and provides many advantages such as boiler design a compact, flexible fuel, high combustion efficiency and reduced emissions of harmful pollutants such as SOx and NOx. Fuel can be burned in this boiler is coal, goods repulsion from the washing of clothes, rice husk, bagasse and other agricultural wastes. Fluidized bed boilers have a wide capacity range between 0.5 T / hr to more than 100 T / hour. When air or gas is distributed uniformly passed upward through bed of solid particles such as sand supported by a fine mesh, the particles do not

will be disrupted at low speeds. As air velocity

gradually rises, it becomes a situation where the particles are suspended in air flow sehinggabed is called "fluidized". With the increase in air velocity, there is bubble formation, strong turbulence, rapid mixing and formation of solid particles rapat.Bed permukaanbed yang properties of boiling liquid and looks like fluid called "bubbling fluidized bed (bubbling fluidized bed)." If the sand particles in a fluidized state is heated to a temperature of flame coal, and coal is injected continuously kebed, coal will burn rapidly danbed achieve a uniform temperature. Fluidized bed combustion (FBC) takes place at temperatures around 840 ° C to 950 ° C. Since this temperature is much below the ash fusion temperature, the melting of ash and associated problems therein can be avoided. Lower combustion temperature is reached due to the high heat transfer coefficient as a result of rapid mixing in the fluidized bed and an effective heat extraction daribed through heat transfer in the pipe and wall beds. Gas velocity is the minimum fluidization velocity and the speed of incoming particles. This ensures a stable and avoid operasibed particle entrainment in the gas. 5.Atmospheric Fluidized Bed Combustion (AFBC) Boilers Most boilers that operate for this type adalahAtmospheric Fluidized Bed Combustion (AFBC) boilers. This tool is just a shellboiler ordinary conventional coupled with a fluidized bed combustor. Such systems have been installed combined

with water tube boilers / boilers of conventional water pipes. Coal crushed to a size 1-10 mm depending on the level and type of coal feeder air into the combustion chamber. The atmospheric air which acts as fluidization and combustion air, is inserted with pressure, after being preheated by the exhaust gas fuel. Dalambed pipes that carry water generally act sebagaievaporator. The gaseous products of combustion through the boiler and super heater from flowing keeconomizer, to dust collectors and air preheater before being discharged into the atmosphere. 6.Pressurized Fluidized Bed Combustion (PFBC) Boiler

In type Pressurized Fluidized Bed Combustion (PFBC), an air compressor supplying Forced Draft (FD), and the combustor is pressurized tank. The rate of heat released is proportional to the tekananbed sehinggabed dalambed which in used to extract large amounts of heat. This will improve the efficiency of combustion and sulfur dioxide generated in the two bond dalambed.Steam pipes, one dibed and one above it. Moving heat from the flue gas of gas turbine power generation. PFBC system can be used for cogeneration (steam and electricity) or combined cycle power generation (combined cycle). Operation combined cycle (gas turbine and steam turbine) increases conversion efficiency the overall rate of 5 to 8 percent. 7.Atmospheric circulating Fluidized Bed Combustion Boilers (CFBC)

In the circulatory system, the bed parameters form daribed floating solids. Solids removed in a relatively dilute phase in the riser, and-comer with a cyclone sebuahdown a cyclone the solids. There are no pipelines located pembangkitsteam dalambed. Power and heating berlebihsteam place in the convection, water wall, at the output of lifter / riser. CFBC boilers are generally more economical than AFBC boilers, for its application in industry requires more than 75-100 T / jamsteam. For large units, the higher the characteristics of CFBC boiler furnace will provide an increasingly good use of space, larger fuel particles, absorbent material residence time for efficient combustion and SO2 capture an increasingly greater, and the easier the application of combustion techniques for NOx control pembangkitsteam than AFBC. Figure 4. CFBC Boilers

8.Stoker Fired Boilers Stokers are classified according to the method of feeding fuel to the furnace and by his jenisgrate. The main classifications are spreader stoker-danchain gateatau travel-gate stoker. • Stokers spreader Stokers spreader utilizing a combination of suspension and pembakarangrat e. Coal is fed continuously into the furnace above bed combustion of coal. Fine coal burned in suspension;

larger particles will fall kegrat e, where the coal will burn coal dalambed thin and fast burning. This combustion method provides good flexibility to load fluctuations, since ignition occurs almost instantly when the firing rate increases. Because of this, the spreader stoker is favored over other jenisstoker in many industrial applications. Figure 5. Spreader Stoker Boiler • Chain-grate stoker-traveling grateatau

Coal is fed onto a moving ujunggrat e steel. Ketikagrat e moving along the furnace, the coal burns before dropping off at the end as ash. It takes a certain skill level, especially when menyetelgrat e, danbaffles air damper, to ensure clean burning and produces a minimum amount of unburned carbon in coal feed abu.Hopper extends along the entire end of the feed coal to the furnace. Sebuahgrat e coal is used to control the speed of the coal being fed to the furnace by controlling ketebalanbed fuel. Size of coal should be uniform because a large chunk is not burn completely in time to reach ujunggrat e. Figure 6. Traveling Grate Boiler 9.Pulverized Fuel Boilers

Most power generating station boiler coal fired pulverized coal, and many water pipes in industrial boilers greater use of coal is also fine. This technology is well developed and there are thousands of units worldwide and more than 90 percent capacity coal combustion is of this type.

For the type of bituminous coal, coal ground to a fine powder, the size of +300 micrometer (m) less than 2 percent and below 75 microns in size by 70-75 percent. It should be noted that the powder is too fine a waste of energy milling. Conversely, too coarse powder that will not burn completely in the combustion chamber and cause greater losses due to unburnt. Coal powder combustion air exhaled by partially enters the boiler plant through a series of noselburner. Secondary and tertiary air may also be added. Combustion takes place at temperatures from 1300 - 1700 ° C, depending on coal quality. Dalamboiler particle residence time is typically 2 to 5 seconds, and the particles should be small enough for complete combustion. This system has many advantages such as the ability to burn different coal quality, fast response to changes in cargo load, the use of air temperature of initial heating

high etc.. One of the most popular system for pulverized coal combustion is tangential combustion by using four buahburner from the four corners to create a fireball in the center of the furnace. Figure 7. Fuel combustion for smooth tangential 10. Waste Heat Boiler

Wherever available waste heat at medium or high temperature, waste heat boiler can be installed

economically. If more daristeam kebutuhansteam produced using hot exhaust gas, can digunakanburner additional use of fuel. Jikasteam not directly be used, steam can be used to produce electric power using steam turbine generators. It is widely used in heat recovery from flue gases from gas turbines and diesel engines. Figure 8. Scheme sederhanaBoiler Waste Heat 11. Thermic Fluid Heaters

Currently, thermic fluid heaters have been widely used in various applications for indirect process heating. By using petroleum fluids as heat transfer media, these heaters provide a constant temperature. Combustion system consists of a fixed grate with the composition mechanical draft. Modern thermic fluid heaters consist of oil-fired a double coil, tigapass construction and fitted with jet system pressure. Thermic fluid, which acts as a carrier

heat, heated in the heater and circulated through the equipment user. Here the fluid is hot to the process through a heat exchanger, then returned to the heating fluid. Thermic fluid flow on the end user is controlled by control valve operated pneumatically, based on the operating temperature. Heaters operate at high or low fire depending on the temperature of return oil, which varies with system load. The advantage of these heaters are:

Operation closed system with minimum losses as compared with the boiler steam.

Operating system is not pressurized even for temperatures around 2500C compared to 40 kg/cm2 tekanansteam needs in sistemsteam yang similar.

automatic control settings, which provide operational flexibility. good thermal ef ficiency due to the absence of heat loss

olehblowdown result, disposal of condensate and flash steam.

The overall economics of thermic fluid heaters depending upon the specific application and reference basis. Thermic fluid heaters with coal-fired thermal efficiency range of 55-65 percent is the most convenient to use compared with nearly most of the boiler. Surviving heat recovery equipment in the flue gas will further enhance the thermal efficiency. Figure 9. Configuration Thermic Fluid Heaters 3. Assessment boiler This section describes the evaluation of the performance of boilers, boiler blowdown, and boiler water treatment. 3.1 Evaluation of the performance of boilers

Boiler performance parameters, such as efficiency and the ratio of evaporation, decreases over time due to poor combustion, heat transfer surface fouling and poor operation and maintenance. Even for a new boiler, for reasons such as poor quality fuel and water quality can lead to poor performance of the boiler. Balance of heat can help in identifying heat loss that can or can not be avoided. Boiler efficiency tests can help in finding the deviation from the best efficiency boiler efficiency and target problem areas for corrective action. a) The heat balance

The process of combustion in the boiler can be described in terms of energy flow diagram. This diagram illustrates graphically how the incoming energy from the fuel is converted into energy flow with a

variety of uses and a flow of heat and energy loss. Thick arrows indicate the amount of energy contained in each stream. Figure 10. Diagram of boiler energy balance

Balance is the balance of total energy heat incoming boiler against leaving the boiler in a different form. The following picture illustrates the various losses that occur for pembangkitansteam. Figure 11. Lost in boilers Coal Fueled

Energy loss can be divided into a loss that is or can be avoided. The aim of the Cleaner Production and / or energy assessment must reduce the loss of which can be avoided, by improving energy efficiency. Losing the following can be avoided or reduced:

flue gas loss: -Excess air (reduce to the minimum depending on the teknologiburner, surgery (control), and maintenance) Flue-gas temperature (derived by optimizing treatment (Cleaning), load; a better burner and boiler technology)

loss due to unburnt fuel in the flue and ash (to optimize the operation and maintenance; teknologiburner better) Losing dariblowdown (fresh feed water treatment, recycling condensate)

Loss of condensate (the largest possible amount of condensate) Convection and radiation (reduced by insulation of the boiler

better) b) Efficiency Boilers Boiler thermal efficiency is defined as the percent of energy (heat) in. used effectively padasteam generated. There are two methods of assessment of boiler efficiency:

Direct Method: the energy gain of the working fluid (water dansteam) compared with the energy contained in fuel boiler.

Indirect Method: efficiency is the difference between loss and energy intake. 3.2Blowdown Boilers

If the water is boiled and dihasilkansteam, dissolved solids contained in water will remain in the boiler. If there is a lot of solids in feed water, solids will terpekatkan and eventually will reach a level where their solubility in water will be exceeded and will precipitate from solution. Above a certain level of concentration, solids are encouraging the formation of foam and causing water entrainment kesteam. Deposition also resulted in the formation of crust on the inside of the boiler, Causes local heating becomes excessive and ultimately lead to failure in boiler pipes.

It is therefore important to control the level of concentration of solids in suspension and dissolved in boiling water. This is achieved by a process called blowing down, certain volume of water released and automatically replaced by feed water. Thus the optimum level of total dissolved solids (TDS) in boiler water and waste solids that have been flat out of solution and that tends to stay on the surface of boiler.Blowdown important to protect the surface of the boiler heat exchanger. However, the blowdown

can be a source of heat loss is quite significant, if done incorrectly. Pengendalianblowdown good boiler can significantly reduce treatment and operational costs that include:

lower pretreatment costs -ups airmake Consumption fewer termination time for treatment is reduced Increased boiler life Use of chemicals for water treatment wil l be lower feed

3.3 Boiler Feed Water Treatment

Memproduksisteam quality depends on proper water treatment to control kemurniansteam, deposition and corrosion. A boiler is part of the boiler system, which receives all the pollutants from the front. Boiler performance, efficiency and service life are a direct result of the election and control of feed water used in boilers.

If the entrance to the boiler feed water, increasing temperature and pressure cause the components of water have different properties. Almost all the components in the feed water in a dissolved state. However, under heat and pressure most of the components dissolved out of solution as solid particulates, sometimes in crystalline form and at other times as bentukamorph. If the solubility of specific components in the water passes, there will be the formation of crust and sediment. Water boilers should be reasonably free from the formation of dense deposits of heat transfer to occur quickly and efficiently and should not be corrosive to metal boiler. a) Control sediment

The precipitate in the boiler can result from feed water hardness and corrosion of the condensate and feedwater systems. Water may occur due to lack of system softening.

Deposition and corrosion causing loss of efficiency that can cause failure in the boiler tube and the inability memproduksisteam. The precipitate act as insulators and slow heat transfer. Large amounts of sediment around the boiler to reduce heat transfer can significantly decrease the efficiency of the boiler. Various types of deposits will affect the boiler efficiency differently, so it is important to analyze the characteristics of the sediment. The insulating effect of sediment led to increased metal temperature boilers and pipe may cause failures due to overheating. b) causing precipitation of Dirt

The most important chemicals in water that affect the formation of salt deposits in the boiler is calcium and magnesium salts, known as hard.

Calcium and magnesium bicarbonate dissolved in water to form a solution of alkali / alkali and salts are known as the hardness of the alkali. Salts are decomposed by heating, releasing carbon dioxide and form a soft mud, which then settles. This is called temporary hardness (hardness that can be removed by boiling).

Calcium and magnesium sulphate, chloride and nitrate, when dissolved in water is chemically neutral and will be known as non-alkaline hardness. Materials are called permanent hard chemicals and forming a hard crust on the surface are difficult to remove. Hardness chemicals regardless of the non-alkaline solution due to reduction in solubility with increasing temperature, with concentration due to

evaporation which took place in the boiler, or by chemical changes become less soluble compounds. c) Silica

The presence of silica in boiler water can increase the formation of a hard crust of silica. Silica can also interact with calcium and magnesium salts, forming calcium silicate and magnesium with a low thermal conductivity power. Silica can improve the deposition on turbine fins, having brought in the form of water drops in steam, or in a form that easily evaporate in the steam at pressure high. d) Processing of internal water

Internal processing is the addition of chemicals to the boiler to prevent scale formation. Crust-forming compounds are converted into free-flowing mud, which can be discarded denganblowdown. This method is limited to the boiler where the feed water containing low salt soft, with low pressure, high TDS content in

boiler can be tolerated, and if a small amount of water. If these conditions are not met then a high lajublowdown required to dispose of sludge. It became uneconomical in relation to the loss of water and heat.

Different types of water sources require different chemicals. Compounds such as sodium carbonate, sodium aluminate, sodium phosphate, sodium sulfite and vegetable components or inorganic compounds can all be used for this purpose. For each water conditions required of certain chemicals. Should consult with a specialist in determining the most suitable chemicals for use in each case. Water treatment only with the internal processing is not recommended. e) External Water Treatment

External processing is used to remove suspended solids, solids telarut (especially calcium and magnesium ions which is the main cause of scale formation) and dissolved gases (oxygen and carbon dioxide). External treatment process are:

ion exchange Deaerasi (mechanical and chemical) Reverse osmosis (reverse os mosis)

Removal of mineral / demineralization

Prior to use the way above, it is necessary to remove solids and water colors of raw materials, because these materials can contaminate the resins used in subsequent processing.

Pre-treatment method is simple sedimentation in settling tanks or settling dalamclarif IERS with the help of coagulant and flocculant. Pressurized sand filters, with aeration to remove carbon dioxide and iron, can be used to remove the metal salts from water wells. The first stage of processing is to remove hardness salts and salt non-hard. Removal of salt only hard-called softening, whereas the total removal of salt from the solution is called the removal of mineral or demineralization. f) Recommendations for the boiler and feed water quality

The impurities found in boiler feed water depends on the quality of the untreated, processing used and the boiler operating procedures. As a general rule, the higher the boiler operating pressure will be greater sensitivity to dirt. 4. Energy efficiency opportunities

This section contains about energy efficiency opportunities related to combustion, heat transfer, avoidable losses, energy consumption for auxiliary equipment, water quality danblowdown.

Loss of energy and energy efficiency opportunities in the boiler can be connected with the combustion, heat transfer, avoidable losses, high energy consumption for auxiliary equipment, water quality danblowdown. Various kinds of opportunities in energy efficiency boiler system to associated with: 4.1 Controlling the temperature of flue

The temperature of the chimney should be as low as possible. However, the temperature should not be so low that water vapor will condense on the chimney wall. It is important for fuels containing sulfur in which at low temperatures would result in sulfur dew point corrosion. Flue temperature greater than 200 ° C indicates the potential for reuse of waste heat. It also indicates there has been scaling on equipment transfer / heat recovery and should be shut down early for cleaning water / flue side. 4.2 Preheating feed water menggunakaneconomizers

Typically, exhaust gas boiler ll modern meninggalkanshe 3pass temperature of 200 to 300 ° C. So, there is potential to recover heat from these gases. Flue gas coming out of a boiler usually

maintained at least at 200 ° C, so that sulfur oxides in flue gas does not condense and cause corrosion on heat transfer surfaces. If you use clean fuels like natural gas, LPG or gas oil, economic heat recovery should be determined as dump gas temperature below 200 ° C. might

Potential energy savings depends on the type of boiler installed and the fuel used. Untukshell boiler with an older model, with the exit flue gas temperature of 260 ° C, should be used sebuaheconomizer to derive the temperature to 200 ° C, which will increase the feed water temperature of 15 ° C. The increase in thermal efficiency will reach 3%. 3pass Untukshell modern boiler fueled by natural gas that comes out flue gas temperature 140 ° C, sebuaheconomizer pengembun will lower the temperature to 65 ° C and increasing thermal efficiency by 5%. 4.3 Preheating of combustion air

Preheating of combustion air is an alternative to feed water heating. In order to improve thermal efficiency by 1 percent, combustion air temperature must be raised by 20 ° C. Almost kebanyakanburner oil and gas used in a boiler plant is not designed for air pre-heater temperature is high. Modern burners can withstand the combustion air preheater

higher, making it possible to consider the unit such as a heat exchanger in the flue gas exit, as an alternative terhadapeconomizer, if room temperature water or a high feed back possible. 4.4 Minimizing Incomplete combustion

Incomplete combustion can arise from lack of air or excess fuel or poor distribution of fuel. It is obvious from the color or smoke, and must be corrected immediately.

In the oil and gas combustion systems, the presence of CO or smoke (only for oil combustion system) with normal air or a large excess indicate a masala on sistemburner. The occurrence of combustion

not perfect due to poor mixing of air and fuel padaburner. Ugly oil combustion can result from improper viscosity, ujungburner damaged, carbonization and damage on ujungburner padadif fusers or pelatsp in n er.

In the combustion of coal, unburned carbon can be a great loss. This occurs at the time taken by grit or the presence of carbon in the ash and can reach more than 2 percent of the heat supplied to the boiler. The size of the non-uniform fuel can also be a cause of incomplete combustion. In chain grate Stokers, a big chunk will not burn completely, while small pieces and air passage, thus causing poor air distribution. In sprinkler Stokers, conditions grate stoker, fuel distributor, air conditioning and combustion systems can affect carbon loss. Increased coal fines also increase carbon loss. 4.5 Control of excess air

Excess air combustion is required at all practices to ensure complete combustion, to obtain the variation of combustion and to ensure satisfactory condition of the chimney for some fuel. Optimal level of excess air for maximum boiler efficiency occurs when the amount of loss caused by incomplete combustion and the loss caused by the heat in the flue gases is minimized. These levels vary depending on furnace design, type burner, fuel and process variables.

Control of excess air at optimum level always resulted in a decrease in the loss of exhaust gas, for every 1 percent reduction in excess air there is an increase of approximately 0.6 per cent efficiency. Various methods are available to control excess air:

oksigenportable analysis tool and draft gauges can be used for

Gravitasi merupakan salah satu contoh bentuk gaya. Gaya sendiri adalah sebuah konsep dalam fisika yang sangat abstrak. Salah satu arti gaya adalah sebuah interaksi antara sebuah benda dengan lingkungannya. Gaya gravitasi adalah sebuah interaksi antara sebuah benda yang bermassa m dengan benda lain disekitarnya. Praktisnya, gaya terjadi disetiap benda yang memiliki massa dengan benda lain yang juga memiliki massa di alam ini.

Satuan gaya, menurut sistem SI adalah Newton.Satuan Newton adalah gaya yang memberikan percepatan 1m/s kepada massa 1 kilogram.Usaha didefinisikan sebagai segala sesuatu yang dilakukan. Jika sebuah gaya sebesar F bekerja pada benda sehingga dapat berpindah sejauh S, maka dapat dikatakan melakukan usaha. Besarnya usaha yang dilakukan sebuah benda , yaitu : W = F x S ; W = Usaha (j), F = Gaya (N), S = Perpindahan (m). Satu usaha yaitu satu jule, satu erg. Satu joule : besarnya usaha yang dilakukan oleh gaya 1 Newton, apabila benda berpindah sejauh 1 meter. Satu erg : besarnya usaha yang dilakukan oleh 1 dyne, apabila benda berpindah sejauh t centimeter. 2 Daya adalah besarna usaha atau energi yang dilakukan persatuan waktu. Beberapa faktor penting yang mempengaruhi besarnya daya yaitu gaya yang dilakukan, jarak perpindahan dan waktu yang diperlukan.Berat benda besarnya tergantung dari massa dan gravitasi. W = m x g (W = berat (N), m = massa (kg), g = gravitasi ).Tekanan adalah besarnya gaya yang bekerja pada benda tiap satuan

luas.